1. Field of the Invention
This invention has relation to foldable stools which can easily, safely and quickly be moved between an upright condition such that they can be supported on a horizontal surface and a compact, folded condition such that they can be easily and conveniently stored or transported when not in use.
2. Description of the Prior Art
It is known to provide folding structures which can be used as dog houses, and for play structures such as, for example, "rocking boats", rocking horses and cradles. See U.S. Pat. No. 4,122,638, granted to O'Brian et al in October of 1978 and an application of O'Brian et al, Ser. No. 752,104, filed Dec. 20, 1976, and incorporated in the O'Brian patent by reference.
The disclosure of the O'Brian et al application was limited to structures where nonfolding side walls, a folding top wall, folding end walls, and a folding bottom wall were all rectangular in shape and where the several hinges which hold these walls together and permit folding were each in parallel relationship to one of mutually perpendicular X, Y or Z axes. This structure disclosed a flashing along the top edge of a roof which was "somewhat resilient in character so as to tend to act as a spring and fit sufficiently closely to the top member [of the roof] so as to serve a locking or holding function" (specification of application Ser. No. 752,104, page 8, beginning on line 18). It also disclosed an overcenter relationship of the walls and hinges, "in providing a sort of toggle-type action in connection with the action of hinges 32 and 36 connecting the end walls 28 and 30 to the side walls 12 and 14 and to one another." (Specification of O'Brian application Ser. No. 752,104, page 11, beginning on line 17). This snap-in-place action placed considerable stress on the hinges and the connection of the walls to the hinges.
The O'Brian application showed a structure which was effective for its intended purpose. However, limitation to the use of entirely rectangular relationships with all hinges pivoting on axes at right angles to other hinges resulted in a structure which was not firm and steady. As it was used more and more for play houses or for its intended purpose, as a dog house, it tended to become "rickety" and to be easily movable out of an exact rectilinear shape.
The structure of the O'Brian patent, U.S. Pat. No. 4,122,638 also relies heavily, if not entirely, on this same kind of "sort of toggle-type action", thus necessarily putting major stresses on the hinges and the connection points of the hinges with the walls. This is a particularly important point in connection with play equipment or in connection with foot stools, step stools or stools to sit upon made in accordance with the present invention.
A preliminary search was made on this invention, and the only patent cited was O'Brian U.S. Pat. No. 4,122,638, discussed above.
Neither the inventor nor those in privity with him are presently aware of any prior art which is closer than that discussed above and are not aware of any prior art which renders unpatentable any of the claims made herein.